DescriptionThis dissertation explores the motivations of local governments in developed countries to engage in cooperative relationships with their less developed counterparts and examines how such motivations change as a function of national and local institutional environments. The dissertation further examines the meaning and determinants of effectiveness in municipal cooperation from the perspective of partners in developed countries. The research for this dissertation took a qualitative comparative approach, focusing on the twinning of sister cities as a form of municipal international cooperation and using two countries, the United States and the Netherlands, and multiple cities within each country as research sites and cases for comparison. Documents and transcribed in-depth interviews with representatives of local governments, local government associations, and town twinning organizations served as the primary data sources for this study. The analysis of the data showed that a range of pragmatic, altruistic, and other types of motivations, which vary across municipalities, guide cooperation between local governments in developed and developing countries and that complex relationships exist between contextual factors and motivations for cooperation. The analysis further showed that definitions of effectiveness vary across municipalities and that multiple factors, internal and external to municipal partnerships, determine the effectiveness of cooperation. The findings support the implementation of a variety of strategies to stimulate cooperation between municipalities in developed and developing countries.